Unfortunately, it is sometimes not even possible to say which solution should be preferred because different branches lead to different sets of packages having higher versions. There is not really an "ultimate" heuristic to determine which of the two sets is better.

However, users are always encouraged to add more constraints to shape the solution, and packagers encouraged to take good care of the metadata.

At prefix we are quite interested in figuring out how we can help packagers to determine e.g. compatibility ranges more correctly by doing static analysis and such things.